Apparatus for handling and top-charging a starter bar

ABSTRACT

A method and apparatus for handling and top-charging a starter bar to the mold of a continuous-casting machine. The apparatus includes a recovery bridge which extends upwardly from the location where the bar is disconnected from the casting. The recovery bridge has means for propelling the bar upwardly and delivering it to a charging car, which runs on tracks above the top of the mold. The charging car has a cog wheel for propelling the bar along its length, and a reel and cable mechanism for lowering the bar into the mold.

United States Patent [191 Grosko et al.

[ July 23, 1974 APPARATUS FOR HANDLING AND TOP-CHARGING A STARTER BAR [75] Inventors: John A. Grosko, West Mifflin Borough, Allegheny County; Melvin G. Short, Pittsburgh; James T. Stull, Jackson Township, Butler County,

all of Pa.

[73] Assignee: United States Steel Corporation,

Pittsburgh, Pa.

[22] Filed: Aug. 2, 1972 [21] Appl. No.: 277,425

52 vs. C]. ..164/274 51 Int. Cl ..B22d 11/08 58 Field of Search 164/274, 282

[56] References Cited UNITED STATES PATENTS 3,682,233 8/1972 Rokop 164/282 3,692,094 9/1972 Wagner "t 164/274 3,702,154 11/1972 Rokop 142/282 X 3,762,462 10/1973 Pietryka 164/274 OTHER PUBLICATIONS Iron and Steel, October 1970, TS 300 l 62, page 293.

Primary Examiner-J. Spencer Overholser Assistant Examiner-John S. Brown Attorney, Agent, or Firm-Walter P. Wood [57] t ABSTRACT A method and apparatus for handling and topcharging a starter bar to the mold of a continuouscasting machine. The apparatus includes a recovery bridge which extends upwardly from the location where the bar is disconnected from the casting. The recovery bridge has means for propelling the bar upwardly and delivering it to a charging car, which runs on tracks above the top of the mold. The charging car has a cog wheel for propelling the bar along its length, and a reel and cable mechanism for lowering the bar into the mold.

6 Claims, 6 Drawing Figures PATENTEDJULZBISH sum 1 or 4 Pmmanm w aeasass sum 3 or 4 APPARATUS FOR HANDLING AND TOP-CHARGING A STARTER BAR This invention relates to an improved method and apparatus for handling and topcharging a starter bar used in a continuous-casting operation.

In a conventional continuouscasting operation, liq uid metal is poured continuously from a tundish into the upper end of a vertically oscillating, open-ended, water-cooled mold. A casting, which is of indefinite length but at this stage has only a solidified outer skin and a liquid core, emergesfrom the lower end of the mold. Thereafter the casting travels betweenseries of rolls, where intense water sprays are applied to its surface to complete the solidification process. The rolls usually include a curved roll-rack, which guides the casting as its direction of travel'changes from vertical to horizontal, followed'by a straightener. In modern low-head casting machines, the core remains liquid even beyond the straightener. This necessitates confin ing the casting within a horizontal roll-rack after it leaves the straightener to prevent it from bulging.

At the beginning ofa casting operation, a starter bar is charged into the mold to close the lower end. As the operation gets underway, the starter bar precedes the casting between therolls therebelow. At some point below the mold the starter baris disconnected from the leading end of the casting and stored in readiness to begin the next'casting operation. If a flexible starter bar is used, the bar usually travels at least through the curved roll-rack and straightener before it is disconnected. To begin each operation with a flexible starter bar, the most common practice is to back the starter bar through the curved roll-rack into the bottom of the mold; This practice is unduly time consuming, requiring car.

FIG. 5 is an elevational-vie'w of a portion of a starter bar of a construction which we may usev in our method and apparatus; and i FIG. 6 is a section on line Vl-VI of FIG. 5 showing one form of device we may use for connecting the starter bar'to a suspending means carried by the charg- FIG. 1 shows diagrammatically one form of continuous-casting machine with which we can use our inven- 10, a straight vertical guide roll-rack 12, a bending-roll unit 13, a curved roll-rack 14, a straightener 15 anda horizontal roll-rack 16. Liquid metal is introduced to the mold from a tundish 17 supported on a turntable 18, whereby the tundish can be swung to positions directly over the mold 'for pouring, or clear of the mold. In the machine illustrated, the bending-roll unit 13 has driven rolls for propelling the casting, the uppermost driven roll 'being indicated at' 19. The machine is equipped with a flexible starter bar 20, which need be only of a length to reach from a few inches above the mold 10 to the uppermost driven roll 19. Certain details of the starter bar are described more fully hereinafter.

ing at least a half-hour turnaround time between casts,

and usually longer. As a'rneans for lessening the turnaround time, it is known to charge the starter bar into the top of the mold. A published description of an installation in which the latter practice is followedappears in Iron and Steel Engineer, October I970, page An object ofour invention is to provide an improved In the drawings:

FIG. .1 is a partly diagrammatic vertical sectional view of a continuous-casting machine equipped with our apparatus for handling and top-charging thestarter bar;

FIG. 2 is a partly diagrammaticsectional view on a larger scale through the recovery bridge embodied in the apparatus taken on line 11-11 of FIG. 1;

FIG. 3 is aside elevational view on a larger scale than FIG. 1 of the charging car embodied in the apparatus;

FIG. 4 is a top'plan view of the charging car;

, The casting machine illustrated is only representative of the type with which ourinvention can be used, and numerous variations are possible. For'example, the machine may be equipped with separate pinch rolls, and the rolls of the bending-roll unit may all be idlers. A curvedmold may be used, in which event the straight guide roll-rack and. bending roll-unit are eliminated. Various rolls along the curved roll-rack may be driven, and the others are idlers. In machines in which the casting solidifies throughout by the time it leaves the straightener, the horizontal roll-rack may be eliminated. Since all the foregoing parts .(except the starter bar) and theirvariations are well known, we have not shown nor described them in detail. In the interest of simplicity, we have, omitted anyshowing of other conventional parts, such as mechanisms for oscillating the mold, and the means for supplying cooling water.

Our starter bar handling apparatus comprises a recovery bridge 24 which slopes upwardly from the exit end of the horizontal roll-rack 16 to a horizontal track 25 supported on a frame 26 above the level of the mold 10; A -guide 27 is pivoted to the lower or receiving end of the bridge. A fluid pressure cylinder-and piston 28 are connected between the bridge and guide for raising and lowering the latter. At the beginningof a casting operation, we lower the guide into alignment with the horizontal roll-rack 16, whereby the guide directs the flexible starter bar 20 upwardly into the recovery bridge 24. When the leading end of the casting arrives at the guide, we operate cylinder 28 to raise the guide about its pivot and thus disconnect the starter bar from the; casting. As known in the art, the starter bar may have a detachable head which stays with the casting when the starter bar is disconnected.

The recovery bridge 24 includes-a fixed frame 31 and a pair of opposed guide channels 32 supported by the frame thereabove (FIG. 2). The receiving and delivery ends of the channels curve rearwardly toward the horizontal roll-rack l6 and track 25 respectively, whereby the channels can receive the starter bar from the guide 27 and deliver it to a charging car 33 on the track. The bridge also includes a series of cog wheels 34 and respective drives therefor spaced along its length. As

shown in'FlG. 2, each cog wheel is fixed to a respective shaft 35 journaled in bearings 36 mounted on pedestals 37. Each drive for the-cog wheels includes a respective motor 38 connected to shaft 35 through suitable reduction gearing. The cog wheels can engage the starter bar to propel the bar up the bridge and deliver it to the charging car 33. I

As shown in FIGS. 3 and 4, the charging car 33 has a frame 39 which is open at its midportion and carries upstanding guides 40 spaced inwardly of its side edges. Series of idler rollers 41 are journaled to the frame 39 along each side of its open midportion to receive the starter bar 20 from the recovery bridge 24. At least one driven cog wheel 42 is journaled to the frame at its open. midportion for engaging and propelling the starter bar along the rollers 41. The drive for the cog wheel is indicatedat 43. The car has wheels 44, at least one of which is connected tov a reversible drive 45lfor propelling the caralong ,its' track 25. The back end of the car carries a transverse bar 46' spaced above the rollers 41 with sufficient clearance that the starter bar 20 can pass therebetween as it is delivered to the car. Bar

46 carries a motor-driven, reel 47. A cable 48 carried by the reel is adapted to be hooked to the trailing end of the starter bar for suspending the bar from the front end of the car. The frame 39 is rounded at its front end as indicated at 49 to enable the starter bar to flex therearound as it is propelled off the car. The front end of the frame carries a retractable roll or pulley 50 and double-acting fluid-pressure cylinders and pistons 51 for advancing and retracting the pulley. Cable 48 passes over the pulley when the pulley is advanced and the cable is suspending the starter bar from the car.

FIGS. 5 and 6 show details of a starter bar 20 which can be handled and charged according to our invention. As FIG. 5 shows, the bar'includes a rigid cross piece 52 at its head end, a plurality of transverse spokes 53, and series of interfitting links 54 hingedly attached to the spokes at either side of the longitudinal center line. The midportions of the spokes are free of links, whereby the cog wheels 34 and 42 can engage the spokes for propelling the bar. The links 54 may be constructed to flex from a straight-line relation only in the counterclockwise direction, as viewed in FIG. 1, or in both directions. Both types are well known. As FIG. 6 shows, the cross piece 52 has a hole 55 which is located on the longitudinal center line of thestarter bar. The end of cable 48 carries a clevis 56. We connect the clevis to the cross piece 52 with a removable pin 57 which extends through the clevis and hole 55 for suspending the starter bar from the cable. The cross piece 52 carries rail sections 58 adapted to engage the detachable starter bar head (not shown).

In operation, we lower the guide 27 at the beginning of a casting operation When the starter bar 20 reaches the guide, the guide directs it up the recovery bridge 24 between the channels 32. As already explained, we raise the guide 27 when the leading end of the casting arrives at the guide to disconnect the starter bar from its head. We operate motors 38 to drive the cog wheels 34 and thus propel the starter bar up the bridge and deliver it to the charging car 33. We use the cog wheel 42 topropel the starter bar along the rollers 41 after the bar clears the bridge. The car is positioned all the way to the right while we deliver the bar to the platform. At

this time pulley 50 is retracted, and cable 48 fully wound on reel 47..We engage .the -clevis 56 with the cross piece 52. I

As soon as the cast is completed, we operate tumtable 18 to swing tundish l7 clearof the mold 10. We insert a temporary protective liner (not shown) in the mold. We run the car 33to the left to a position in which the front end of its frame 39 is directly over the mold, as FIG. 1 shows. We operate the cog wheel 42 to propel the starter bar off the front end of the car and charge it into the top of the mold. When the starter bar clears the car, we advance pulley 50 and use the cable 48 to lower the starter bar to a position in which its leading end-is engaged'by the driven roll 19. We disconnect the cable from the bar and apply the detachable head. We use the driven roll 19 to lower the starter bar to its proper position in the mold for starting the next cast. We pack the space around the head in the conventionalfashion and remove the temporary liner.

The starter bar is thinner than the mold and the path defined bythe rolls, but the driven rolls can shift sufficiently to engage the starter bar for propelling it, as is conventional. v v

From the foregoing description, it is seen that our invention affords a simple apparatus for top-charging a starter bar, and a method of accomplishing this operation-with a minimum turnaround time. Before a cast is finished, the starter bar is loaded on the charging car and the cable connected thereto in readiness for charging into the mold. Since the bar is short in length, little time is consumed in running it from the car into the mold.

Weclaim:

1. In a continuous-casting machine which includes! a mold; v

a series of rolls below said mold, which series includes a. curved roll-rack for guiding a casting formed in said mold as its direction of travel changes from vertical to horizontal;

a flexible starter bar for preceding a casting through said series of rolls; r

and means following said curved roll-rack for discon- I necting said starter bar from the leading end of a casting;

the combination therewith of an apparatus for handling and top-charging said starter bar to said mold for beginning a casting operation, said apparatus comprising:

a recovery bridge for said starter bar, which bridge has a receiving end adjacent said disconnecting means and an unobstructed delivery end thereabove and includes an opposed pair of guide channels for receiving said starter bar,

a track extending-from adjacent the delivery end of said bridge to a' location above'and adjacent said mold,

a charging car movable along said track between a first position adjacent said bridge and a second position adjacent said mold;

a series of driven cog wheels in said bridge engaging said starter bar when the latter is received within said channels for propelling said'starter bar from .said disconnecting means and delivering it to said car;

said channels curving toward said rollsand toward said track at the receiving and delivering ends respectively of said bridge; and

means on said car for lowering said starter bar into said mold.

2. In a continuous casting machine which includes a mold, a curved roll-rack below said mold, a flexible starter bar, and means following said curved roll-rack for disconnecting said starter bar from the leading end of a casting, the combination therewith of an apparatus for handling and top-charging said starter bar to said mold, said apparatus comprising:

a recovery bridge having a receiving end adjacent said disconnecting means and a delivery end thereabove and including a pair of opposed channels for receiving said starter bar between them, said channels curving toward said disconnecting means and toward said mold at the receiving and delivery ends respectively of said bridge;

a series of driven cog wheels in said bridge engaging disconnecting means includes a guide pivoted to said bridge adjacent its receiving end, and motive means connected to said guide for moving it between a lowered position for directing said starter bar into said bridge and a raised position for effecting disconnect of said starter bar from the casting.

4. An apparatus as defined in claim 1 in which said car includes series of idler rollers for supporting said starter bar, and means for propelling said starter bar along said idler rollers, and in which the means on said car for lowering said starter bar includes a reel and a cable on said reel adapted to be connected to one end of said starter bar. g

5. An apparatus as defined in claim 4 in which the end of said car nearer said mold is rounded to allow said starter bar to flex as it moves thereacross, and in which said car includes a pulley at said rounded end for guiding said cable'and means connected to said pulley for advancing and retracting it.

6. An apparatus as defined in claim 1 in which the series of rolls in said casting machine include at least one driven roll spaced below said mold, and said starter bar is of relatively short length sufficient to extend only from a few inches above said mold to said driven roll. 

1. In a continuous-casting machine which includes: a mold; a series of rolls below said mold, which series includes a curved roll-rack for guiding a casting formed in said mold as its direction of travel changes from vertical to horizontal; a flexible starter bar for preceding a casting through said series of rolls; and means following said curved roll-rack for disconnecting said starter bar from the leading end of a casting; the combination therewith of an apparatus for handling and topcharging said starter bar to said mold for beginning a casting operation, said apparatus comprising: a recovery bridge for said starter bar, which bridge has a receiving end adjacent said disconnecting means and an unobstructed delivery end thereabove and includes an opposed pair of guide channels for receiving said starter bar, a track extending from adjacent the delivery end of said bridge to a location above and adjacent said mold, a charging car movable along said track between a first position adjacent said bridge and a second position adjacent said mold; a series of driven cog wheels in said bridge engaging said starter bar when the latter is received within said channels for propelling said starter bar from said disconnecting means and delivering it to said car; said channels curving toward said rolls and toward said track at the receiving and delivering ends respectively of said bridge; and means on said car for lowering said starter bar into said mold.
 2. In a continuous casting machine which includes a mold, a curved roll-rack below said mold, a flexible starter bar, and means following said curved roll-rack for disconnecting said starter bar from the leading end of a casting, the combination therewith of an apparatus for handling and top-charging said starter bar to said mold, said apparatus comprising: a recovery bridge having a receiving end adjacent said disconnecting means and a delivery end thereabove and including a pair of opposed channels for receiving said starter bar between them, said channels curving toward said disconnecting means and toward said mold at the receiving and delivery ends respectively of said bridge; a series of driven cog wheels in said bridge engaging said starter bar when the latter is received between said channels for propelling said starter bar from said disconnecting means toward said mold; and a car movable between the delivery end of said bridge to said mold for carrying said starter bar from said bridge to said mold and lowering said starter bar into said mold.
 3. An apparatus as defined in claim 1 in which said disconnecting means includes a guide pivoted to said bridge adjacent its receiving end, and motive means connected to said guide for moving it between a lowered position for directing said starter bar into said bridge and a raised position for effecting disconnect of said starter bar from the casting.
 4. An apparatus as defined in claim 1 in which said car includes series of idler rollers for supporting said starter bar, and means for propelling said starter bar along said idler rollers, and in which the means on said car for lowering said starter bar includes a reel and a cable on said reel adapted to be connected to one end of said starter bar.
 5. An apparatus as defined in claim 4 in which the end of said car nearer said mold is rounded to allow said starter bar to flex as it moves thereacross, and in which said car includes a pulley at said rounded end for guiding said cable and means connected to said pulley for advancing and retracting it.
 6. An apparatus as defined in claim 1 in which the series of rolls in said casting machine include at least one driven roll spaced below said mold, and said starter bar is of relatively short length sufficient to extend only from a few inches above said mold to said driven roll. 